Class: World botec.py

A world represents a physical object in the system.

Base Classes
Location
Methods
__getitem__
```__getitem__ ( self,  key )

```
__init__
```__init__ (
self,
system,
data=None,
**keywords,
)

```
__str__
```__str__ ( self )

```
albedo
```albedo ( self )

```

The body's visual geometric albedo. [dimensionless]

allNames
```allNames ( self )

```
alternateNames
```alternateNames ( self )

```
altitudeAtPressure
```altitudeAtPressure ( self,  pressure )

```

The altitude for the specified pressure. [m]

```angularRadiusFromDistance ( self,  distance )

```

The angular radius of this object when viewed from the given distance. [rad]

```angularRadiusFromPrimary ( self )

```

The apparent angular radius of this body as seen from its primary. [rad]

```angularRadiusOfPrimary ( self )

```

The apparent angular radius of the primary as seen from this body. [rad]

```angularRadiusOfSecondary ( self,  secondary )

```

The apparent angular radius of the secondary body as seen from this body. [rad]

apoapsis
```apoapsis ( self )

```

The periapsis of this orbit. [m]

apostationaryAltitude
```apostationaryAltitude ( self )

```

The apostationary distance expressed as an altitude. [m]

apostationaryDistance
```apostationaryDistance ( self )

```

The distance an object orbiting this body would have to be in order for its orbital period to equal the rotation period of the body itself. [m]

areicAtmosphereMass
```areicAtmosphereMass ( self )

```

The mass of the atmosphere per unit area. [kg/m^2]

asteroids
```asteroids ( self )

```

Get the list of this body's asteroids.

atmosphereMass
```atmosphereMass ( self )

```

The total mass of the atmosphere. [kg]

barycenterDistanceWithSecondary
```barycenterDistanceWithSecondary ( self,  secondary )

```

Compute the barycenter distance between this body and its secondary (measured from the primary). [m]

biozone
```biozone ( self )

```

The range of distances that roughly correspond to the habitable zone for this self-luminous object. [m, m]

centripetalAccelerationAtSurface
```centripetalAccelerationAtSurface ( self )

```

The centripetal acceleration a particle has to experience at this body's surface to maintain constant distance from its center. [m/s^2]

circumference
```circumference ( self )

```

The body's circumference. [m]

class_
```class_ ( self )

```
comets
```comets ( self )

```

Get the list of this body's comets.

crossSectionalArea
```crossSectionalArea ( self )

```

The body's cross-sectional area. [m^2]

density
```density ( self )

```

The density of this object. [kg/m^3]

designation
```designation ( self )

```
diameter
```diameter ( self )

```

The body's diameter. [m]

distanceAndPhaseAtCentralAngle
```distanceAndPhaseAtCentralAngle (
self,
other,
centralAngle,
)

```

For another sibling body at some central angle relative to this body, compute the distance to the body and its phase and return them. [m, 1]

distanceForIntensity
```distanceForIntensity ( self,  intensity )

```

The distance at which one would receive this specified intensity from this (self-luminous) body. [m]

distanceToSecondary
```distanceToSecondary ( self,  secondary )

```

The distance to the specified secondary body. [m]

eccentricity
```eccentricity ( self )

```

The eccentricity of the body. [dimensionless]

ellipticity
```ellipticity ( self )

```

The ellipticity of this body; the ratio of the difference in equatorial and polar radii to the equatorial radius. [dimensionless]

emissivity
```emissivity ( self )

```

The emissivity of the body. [dimensionless]

ensure
```ensure ( self,  system )

```

Normalize all the figures provided; return the primary (object) and distance (in metres) as a 2-tuple.

```equatorialRadius ( self )

```

The equatorial radius of the body. [m]

escapeSpeedFromDistance
```escapeSpeedFromDistance ( self,  distance )

```

The speed required to escape the gravitational field of this object at the specified distance. [m/s]

escapeSpeedFromPrimary
```escapeSpeedFromPrimary ( self )

```

The speed required for this body to escape its primary. [m/s]

escapeSpeedFromSurface
```escapeSpeedFromSurface ( self )

```

The speed required to escape this body from its surface. [m/s]

get
```get (
self,
key,
default=None,
)

```
gravitationalBindingEnergy
```gravitationalBindingEnergy ( self )

```

The gravitational binding energy of the object. [J]

gravityAtDistance
```gravityAtDistance ( self,  distance )

```

The gravitational field strength created by this object at the given distance. [m/s^2]

gravityAtSurface
```gravityAtSurface ( self )

```

The gravitational field of this body at its surface. [m/s^2]

```had ( self,  key )

```
has
```has ( self,  key )

```
```hasRetrogradeRevolution ( self )

```

```hasRetrogradeRotation ( self )

```

hasSurface
```hasSurface ( self )

```

Does the body have a physical surface?

```hillRadius ( self )

```

The Hill radius, which is the distance at which the tidal strength of this body and its primary are equal. [m]

idealTemperature
```idealTemperature ( self,  emissivity=None )

```

The equilibrium thermodynamic temperature of this body if it were treated as an ideal emitter with the specified emissivity. [K]

inclination
```inclination ( self )

```

The inclination of this body's orbit with the ecliptic. [rad]

indirectIntensityAtDistance
```indirectIntensityAtDistance (
self,
distance,
phase=1.0,
)

```

The indirect intensity from reflected power on this object (which is at the given phase) at the given distance. [W/m^2]

intensityAtDistance
```intensityAtDistance ( self,  distance )

```

The direct irradiance from this (luminous) object at the given distance. [W/m^2]

intensityFromPrimary
```intensityFromPrimary ( self )

```

The direct irradiance from this object's (luminous) parent at the distance of this body. [W/m^2]

intensityFromRoot
```intensityFromRoot ( self )

```

The brightness of this object due to its luminous root parent. [W/m^2]

interceptedPower
```interceptedPower ( self )

```

The total rate of intercepted power on this body. [W]

interceptedPowerAtSurface
```interceptedPowerAtSurface ( self )

```

The total rate of intercepted power on this body at its surface. [W]

isInclined
```isInclined ( self )

```

Is the body highly inclined?

isLuminous
```isLuminous ( self )

```

Is the body self-luminous?

isNonSpherical
```isNonSpherical ( self )

```

Is the body decidedly non-spherical?

isOblate
```isOblate ( self )

```

Is the body significantly oblate?

isOblique
```isOblique ( self )

```

Is the body obliquely tilted?

isRoot
```isRoot ( self )

```
isSynchronous
```isSynchronous ( self )

```

Is the body synchronous with respect to its primary?

luminosity
```luminosity ( self )

```

The body's luminosity. [W]

mass
```mass ( self )

```

The mass of the body. [kg]

massEnergy
```massEnergy ( self )

```

The mass-energy of the object according to Einstein. [J]

massRatio
```massRatio ( self,  barycentric=False )

```

The mass of this body expressed in units of its primary, optionally barycentric (expressed in units of the sum of the two). [dimensionless]

maximumTidalStrengthFromSecondaries
```maximumTidalStrengthFromSecondaries ( self )

```

The maximum "tidal strength" on this body inducde by all of its secondaries. [kg/m^3]

maximumTidalStrengthFromSibling
```maximumTidalStrengthFromSibling ( self,  sibling )

```

The maximum possible "tidal strength" on this body from the specified sibling (in orbit around the same primary). [kg/m^3]

name
```name ( self )

```
netAccelerationAtSurface
```netAccelerationAtSurface ( self )

```

The net `weight` (in acceleration) of a particle at rest on the surface, taking into account centrifugal pseudoforces. [m/s^2]

normalizedMomentOfInertia
```normalizedMomentOfInertia ( self )

```

The normalized moment of inertia, that is the coefficient k when the moment of inertia is written I = k M R^2. [dimensionless]

number
```number ( self )

```
obliquity
```obliquity ( self )

```

The obliquity of this body's axial tilt with respect to its orbital plane. [rad]

opticalDepth
```opticalDepth ( self )

```

The ring system's optical depth. [dimensionless]

orbitalAngularMomentum
```orbitalAngularMomentum ( self )

```

Orbital angular momentum around the primary. [kg m^2/s]

orbitalAngularSpeedAtDistance
```orbitalAngularSpeedAtDistance ( self,  distance )

```

The angular speed an object would have at the given distance while in orbit around this body. [rad/s]

orbitalArea
```orbitalArea ( self )

```

The plane area of the body's orbit. [m^2]

orbitalKineticEnergy
```orbitalKineticEnergy ( self )

```

The orbital kinetic energy. [J]

orbitalMomentOfInertia
```orbitalMomentOfInertia ( self )

```

The moment of inertia for revolution. [kg m^2]

orbitalPeriodAtDistance
```orbitalPeriodAtDistance ( self,  distance )

```

The orbital period an object would have at the given distance while in orbit around this body. [s]

orbitalPeriodAtSurface
```orbitalPeriodAtSurface ( self )

```

The orbital period an object would have to have if just at the surface of this body, ignoring atmosphere. [s]

orbitalPotentialEnergy
```orbitalPotentialEnergy ( self )

```

The orbital potential energy. [J]

orbitalSpeedAroundPrimaryAtDistance
```orbitalSpeedAroundPrimaryAtDistance ( self,  distance )

```

Return the instantaneous orbital speed of this body in orbit when its speed is at the specified distance. [m/s]

orbitalSpeedAtDistance
```orbitalSpeedAtDistance ( self,  distance )

```

The orbital speed an object would have at the given distance while in orbit around this body. [m/s]

orbitalSpeedAtSurface
```orbitalSpeedAtSurface ( self )

```

The orbital speed an object would have to have if just at the surface of this body, ignoring atmosphere. [m/s]

orbitalTotalEnergy
```orbitalTotalEnergy ( self )

```

The sum of the kinetic and potential energies. [J]

periapsis
```periapsis ( self )

```

The periapsis of this orbit. [m]

period
```period ( self )

```

The body's rotation period. [s]

planets
```planets ( self )

```

Get the list of this body's planets.

```polarRadius ( self )

```

The polar radius of the body. [m]

```portionOfOrbitInShadow ( self )

```

Calculate the portion (dimensionless) of this satellite's orbit during which it is in the shadow of its primary. This does not take into account the motion of the primary around the Sun itself. [1]

pressure
```pressure ( self )

```

The body's pressure at its surface. [Pa]

pressureAtAltitude
```pressureAtAltitude ( self,  altitude )

```

The pressure at the specified altitude. [Pa]

```radius ( self )

```

The (volumetric mean) radius of the body. [m]

reflectedPower
```reflectedPower ( self )

```

The total rate of reflected power on this body. [W]

rings
```rings ( self )

```

Get the list of this body's rings.

rocheLimitForDensity
```rocheLimitForDensity ( self,  density )

```

The Roche limit for this body for an object of the specified density. [m]

rotationSpeed
```rotationSpeed ( self )

```

The tangential rotation speed at the equator. [m/s]

rotationalAngularMomentum
```rotationalAngularMomentum ( self )

```

The rotational angular momentum. [kg m^2/s]

rotationalAngularSpeed
```rotationalAngularSpeed ( self )

```

rotationalKineticEnergy
```rotationalKineticEnergy ( self )

```

The rotational kinetic energy of the object. [J]

rotationalMomentOfInertia
```rotationalMomentOfInertia ( self )

```

The rotational moment of inertia. [kg m^2]

satellites
```satellites ( self )

```

Get the list of this body's satellites.

scaleHeight
```scaleHeight ( self )

```

This body's atmosphere's scale height. [m]

secondaries
```secondaries ( self )

```
select
```select ( self,  filterFunc )

```
solidAngleFromDistance
```solidAngleFromDistance ( self,  distance )

```

The solid angle subtended by this object when viewed from the given distance (for small angles). [sr]

solidAngleFromPrimary
```solidAngleFromPrimary ( self )

```

The solid angle subtended by this body as viewed from its primary. [sr]

solidAngleOfPrimary
```solidAngleOfPrimary ( self )

```

The solid angle subtended by the primary as viewed from this body. [sr]

solidAngleOfSecondary
```solidAngleOfSecondary ( self,  secondary )

```

The solid angle of the specified secondary body as viewed from this body. [sr]

sphereOfInfluence
```sphereOfInfluence ( self )

```

The sphere of influence for this body; for a satellite of this body to be relatively stable its orbit needs to be completely within the sphere of influence. [m]

surfaceArea
```surfaceArea ( self )

```

The body's total surface area. [m^2]

surfaceBrightness
```surfaceBrightness ( self )

```

The total surface brightness of this object, either by self-luminosity or reflection. [W/m^2]

temperature
```temperature ( self )

```

The body's surface temperature. [K]

tidalStrengthAtDistance
```tidalStrengthAtDistance ( self,  distance )

```

The "tidal strength" of this object due to its gravity at the specified distance. Note that this tidal strength does not represent a physical quantity but is instead intended to be used to scale relative to other objects. [kg/m^3]

tidalStrengthFromPrimary
```tidalStrengthFromPrimary ( self )

```

The "tidal strength" on this body induced by its primary. [kg/m^3]

tidalStrengthFromSecondary
```tidalStrengthFromSecondary ( self,  secondary )

```

The "tidal strength" on this body induced by the specified secondary body. [kg/m^3]

tidalStrengthFromSelfAtSurface
```tidalStrengthFromSelfAtSurface ( self )

```

The "tidal strength" experienced by an object on the surface of this body from the body's gravitational field itself. [kg/m^3]

tidalStrengthRangeFromSibling
```tidalStrengthRangeFromSibling ( self,  sibling )

```

The range in "tidal strengths" on this body from the specified sibling (in orbit around the same primary). [kg/m^3]

tisserandParameter
```tisserandParameter ( self,  major )

```

The Tisserand parameter for this object with respect to the given major planet. [dimensionless]

totalAngularMomentum
```totalAngularMomentum ( self )

```

The sum of the rotational and orbital angular momenta. [kg m^2/s]

type
```type ( self )

```
volume
```volume ( self )

```

The body's volume. [m^3]

zone
```zone ( self )

```